How can I enable dark mode on Firefox on Windows 7 so that the settings page has a dark mode?

How can I enable dark mode on Firefox on Windows 7 so that the settings page (about:preferences#home) has a dark mode?

I unsuccessfully tried:

• using the Dark Reader Firefox extension.
• using Firefox' native dark mode (customize -> themes -> dark)

The settings page:

2 Answers

Great answer by Backseat-Driver on reddit:

You can tell Firefox that you want dark mode by adding ui.systemUsesDarkTheme [number] in about:config and setting the value to 1.

• 0: light
• 1: dark
• 2: no-preference

Any other value and Firefox will use light.

Tested with Firefox 75.0 64-bit on Windows 7 SP1 x64 Ultimate.

1. Go to settings at the top right corner.
2. Click customize.
3. Click Themes.
4. Select dark.
5. Click the ready button on the right down corner.

The settings page at about:preferences#home will remain the same.